Suspended electric dental motor.



No. 820,781. PATENTED MAY 15, 1906. J. F. HAMMOND.

SUSPENDED ELECTRIC DENTAL MOTOR. APPLIOATION FILED APR. 27, 1905.

2 SHEETSr-SHEET 1.

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J. F. HAMMOND. SUSPENDED ELECTRIC DENTAL MOTOR.

APPLICATION FILED APR.27, 1905.

' 2 SHEETS-SHEET 2.

"UNITED STATES PATENT OFFICE.

JOHN, F. HAMMOND, OF BREWSTER, NEW YORK.

I sUSPEuoE ELEYO'VI'RIO DENTAL mo'ron.

Specification of Letters Patent.

ratented May 15, 1906.

Application filed April 27, 1906- Berlal No- 257,597.

To all whom it may concern:

Be it'known that I, JOHN F. HAMMOND, a citizen of the United States, residin at Brewster, in the county of Putnam an State of New York, have invented certain new and useful Improvements in Suspended Electrical Dental Motors, of which the following is a specification.

This invention has reference to the motors used by dentists for operating upon the teeth of a patient reclinin in a suitable chair and for which purpose t e motor is suspended, whereby it can swing horizontally and can, further, be raised or lowered in the various positions throu h which swung.

One of the b ects of the invention is to provide an improved meansfor counterbalancing a motor, and especially an electric motor,

: vide, in such a device, means for in such adjusted positions.

A further object of the invention is to procounterbalancing the motor in its normal position and means cooperating with said balancing means to properly balance the motor when moved above or below said normal position.

A further objectof the invention is to provide means for suitably suspending the motor whereby it can rock on its axis of suspension and means whereby the motor can be removed from such suspens1on when swung to a position transverse to its normal position.

A further object of the invention is to provide an improved form of means for conveying the current to such a form of suspended member. I

A further obj set of the invention is to pro-' vide, ina suspended dental motor operating a flexible shaft, means for readily connecting and disconnecting the flexible shaft with the motor.

Another object of the invention is to pro-, vide, in an electric suspended dental motor operating a flexible shaft, means for insulating the flexible shaft from the motor, thereby preventing any possibility'of current from the same passing through the person operupon.

In the drawings accompanying andform- 'ing part of this specification are shown em bodiments of'the present invention, where- 1n Figure 1 is a side elevation. Fig. 2 is a vertical middl section of the motor and suspended mean Figs. 3, 4, and 5 are detail views of the means for conveying current from the yoke to the motor. Fig.- 6-is a tor and supporting-yoke.

broken vertical section of the supporting means and the counterbalancing means carried thereby. Fig. 7'is an enlarged sectiona broken view of the springs and other cooperating members shown in Fig. 6. Fig. 8 is a vert1cal section through a portion of the mo- Fig. 9 is a fragmentary si e view of the motor-frame shown in Fig. 8. Fi 10 is a transverse section on thellne a: a: s own in Fi 1. Fig. 11 is a transversesection throug the member by which the yoke and motor are flexibly suspended from the arm. 'Fig. 12 is a longitudinal sectional View through a connection of the flexible shaft with the shaft of the motor, and Fig. 13 shows the motor being removed from the yoke.

The present embodiment of the invention, as shownin Fig. 1, comprises a suitable arm 15, that is suitably supported at one end to swing in a vertica plane, and from its upper or free end is suspended a suitable motor 16 by means of a member'17 having a ivotal connection with the end of the arm. 11 connection with these three membersthe arm, the motor, and the suspending member-is provided a supporting the arm and connected with suitable counterbalancinig means, whereby when the arm is moved om the horizontal position in which it is illustrated to the inclined position a, (indicated in broken lines,) wherein it will be observed thedraft of the motor suspension on the arm is decreased by reason of the distance between the vertical line of suspension of the motor and the pivotal point of the arm being lessened, such counterbalancing means will compensate for this change of position and will properly. balance the motor, and not only will it counterbalance 'tor in the two said the mothe same time also swing in' a horizontal plane in any of its positions in such vertical plane comprlses an upright 18, supported to rotate 191 '19, that may include a ball-bearing 20 to reduce friction. The upright member com-,

prises a head 21, carrying a suitable vertical pulley 22 and having a neck 23, which has a pin connection with the upright tube 18.

his upright. tube passes through a suitable aperture 1n the lower bracket 191', fitting loosely therein, and has aball-bearing bemember attached to positions, but in all posi- I on a vertical axis by means of two brackets 2 IIO , outer extremity, and thence passing u ward -Ju'st fbe'low the bracket 191,.a hinged member 26is-securedto the tube and has two ap- J ertured arms 27, between which the arm ispivotally mounted on a vertical axis. The

arm 15 is supported by means of a flexible cable 28, secured to the arm, preferably, at its and around a guide-pulley 22, from w 'ch it asses downward through theu right 18 and Brackets supporting it. The ower end of the cable is connected with a suitable counterbalancing-weight 29. The motor 16, be-

ing supported by a suspending member 17, having a swinging connection with theend of'the arm 15 but arranged to sup ort the member at a ed distance from sai end in the several positions of the arm when the motor is moved u ward to the position indi cated in broken es in Fig. 1, it will be seen that the arm will not be erpendicular to the upright, but inclined t ereto, which will bring its motor-carrying end considerably nearer the vertical line passing through the hinge of the arm. By moving to this position the end of the arm will evidently be brought much nearer'to the pulley 22, which will permit the weight to fall to about the po sition indicated in broken lines. This change of position evidently will exert a much less draft on the cable 28 to support and counterbalance the weight'of the arm and motor,

I and hence such'weight as would properly counterbalancethe arm and motor in the horizontal position will now overbalance such draft on the cable and would tend to raise the, arm or retain it in such position, a and such effect .weu1d assert itself very shortly afterthe arm left the horizontal post'- v tion-and increase from the horizontal position as long as its upward movement decreased the distance between the extremity of the arm and the pulle In order to overcome such tendency of t e weight, a suitable spring is provided that will have the effect of partiall supporting the'weight and decreasi the lower extremity of the ing its raft on the cable as the arm and motor are swung upwardly. In Figs. 6 and 7 areshown one form of such means in which a coil-spring 30 has its upper end secured to ead 21, the spring being secured thereto by a screwing motion. To t e lower extremity of su-chspring' is secured a collar 31, its threaded exterior en-- gagin' the c-onvolutions of the spring. A 'cylin er-tube 32 is secured to the weight a and extends u ward into the upright tube H18, the cable 28 passing from the pulley ter than the 30, is secured to the inner tube 32 above the collar 31. The collar is so arranged that the arm can swin from the horizontal position to a position indicated by the broken line a without engaging the collar; but upon the arm swin ing upward the lowering of the weight W51 move the inner tube 32 downward, and the washer will enga e the collar 31 and distend the spring 30. his will evidently counteract the draft of the weight on the cable and will serve to counterbalance the decreased draft on the cable b reason of the angular position assumed by t e arm.

Should the motor be thrown u "quickly and the weight dropped rapidl t ereby increasing its draft by reason 0 the momentum of the weight, it is desirable to provide a cushioning device to an ment the eiiect of the distending spring an to act as a kind of safety stop at such stage. One form of means for accomplishing such result is shown as comprising a coil-spring engaged by the collar 31. A tube 35 is threaded into the lower extremity of the upright tube 28 and locked in lace by lock-nut 36, and the lower end of tu e 35 is closed, but has a central opening in which slides the inner tube 32. A coil-spring37 is placed loosely around the tube 32 at the bottom of such tube 35, and when thearm approaches its dotted-line position b the collar 31 will strike this spring 37 and dpressing it will arrest the further downwar movement of the weight and inner tube, and thereby arrest the cable and arm. By screwing the tube 35 up or down, the range of movement of the washer 31, and consequently of the arm and motor, is adjusted.

When the arm is moved downward from the position It to the osition c, the wei ht 29 will counterbalance t e draft on the ca le 28 by the arm and motor; but when moved downward from the. 'osition c to the horizontal thecab e. Hence suitable means must be supplied to augment the draft on the cable by the weight. A convenient means for increasing such draft is shown in Figs. 6 and 7 as comprising a coil-spring 38,.loosely surrounding the lnner tube 32 and engagin the washer 34 on the tube, but being free cm the surrounding coil-spring 30. This spring is so proportioned that upon the arm moving downward from the position 0 the consequent elevation of the weight and inner tube will cause the spring 38 to be compressed between the washer 34 and the lower face of the neck on the head 21. pose the upward movement of the wei ht and increase the draft on the cable 28, which will evidently counterbalance the increased draft cnthe cable by the arm and motor.

The leads or conductor-wires for conveying the current to the electric motor 16 are con veniently arranged by supporting them on This will evidently oposition it wiincrease the draft on the arm 15 or passing them thcrethrough by using a tubular arm. From the end ofthe arm the leads pass downward contiguous to the cable-support 17 for the motor 16. By this arrangement it will be seen that the cable. is iractically neither distended nor compressed in the several positions of the arm and motor, it sjmply receiving a slight flexure adjacent to the swinging support of the arm and also at'the swinging connection" at the support 17 with the extremity of the arm, which can easily be arran ed by using a flexible cable at such places offlexure. The support 17. may be arranged as shown in section in Fig. 11, at the center being a flexible sup- )ortingcable, surrounded by four or more insulated flexible leads, where it is desired to use separate leads for the field and the armature, and the whole incased in a suitable covering 40. In Fig. 10 is shown the arrangement of four leads and the supporting-cable 28, where they en age the curved extremity 41 of the arm 15, t 1e supporting-cable 28 being at the middle and the pairs of leads on each side thereof, the curvature preventing the sharp fiexure of such flexible members when the arm is swung and the angle of the flexible members with the arm is changed.

A convenient way for supporting the motor 16 is to provide a frame or yoke 42, to the ends of which the frame of the motor is pivoted. To convey current to the motor, swinging on such pivots at the extremities of onearm of the yoke a pair of spring-arms 43 are secured and connected with two of the leads 38, but insulated from the frame and each other. These arms bear on a pair of pins 44, respectively, passing through insulated bushings 45, and press them against arc-shaped contact-plates 46, carried by the frame of the motor, but insulated therefrom. From these contact-plates wires 47 lead to the electrical parts of the motor. By this construction the motor can swing a considerable distance on the pivots yet the pins still be in contact with the plates 46 and convey current to the motor. Where it is desired to run two sets of leads, such arrangement of brushes and contact-plates is duplicated on the other side of the motor, one set of brushes connecting with the field and the other set with the armature or one of each kind on each side, as most convenient. A modification of such arrangement is shown in Figs. 8 and 9, in which a pair of brushes 48 are carried by the motor-frame and engage with a pair of insulated contact-plates 49, similar to the contact-plates 46, but which are secured to the inner face of the extremity of the yoke, the leads 38 being connected with the insulated plates by passing through the frame 42. This arrangement is duplicated on the other side of the motor, where separate armature and field leads are provided.

The motor 16 is suspended from the yoke 42 in such a manner that by withdrawing the journals a short distance and then swinging the motor from its normal position to a position transverse thereto or at right angles therewith the motor can be withdrawn from the journals; but in its normal position it cannot be withdrawn from the journals, because it would at once engage the yoke 42. The yoke 42 at each end is provided with a screw 62, located in a threaded bore 63 in the oke. In the motor-frame at each side is a socket 64, into which projects the end of the screw 62. In its normal position a flange 66 on the screw 62 stands adjacent to the motorframe. on each side of the motor-frame is a channel 65, that is vertical when the motor is in its normal position and extends from the bore 64 downward to the end of such straight side of the frame, the width of the channel being slightly larger than the diameter of the bearing portion of the bolt 62. When it is desired to remove the motor, the screw-bolts 62 are screwed outward until the flange 66 engages the inner face of the end of the yoke, which will prevent further withdrawal of the bolt. When in this osition, the end portion of the screw will stiil have a supporting engagement with the walls of the bore 64, but it will be in alinement with the channel 65. The motor is now swung to a transverse position or through an arc of ninety degrees and thereupon is moved in the direction of the channel 65, so that the ends of the bolts will slide through this channel, as indicated in Fig. 13, until the bolts have passed entirely through the channel, which will free the motor from the bolts. The motor is returned to its position in the same manner and then the bolts screwed inwardly to their former position. By this arrangement it will be seen that it is not necessary to remove any part or parts of the device in order to remove the motor from the yoke, but merely to screw out the bolts for the limit of their movement. This will obviate the danger of any parts becoming mislaid or lost.

For the purpose of removably attaching the flexible cable generally used with suspended dental motors to the motor and driving shaft means are provided, such as shown in Figs. 1 and 12, comprising, essentially, a skeleton frame or member 50, that is removably secured to the frame of the motor which carries the flexible shaft and which is also preferably suitably insulated, whereby it is impossible for current from the motor to flow into the tool or instrument attached at the end of the flexible shaft and thereby reach the person operated upon. The skeleton member 50 has a threaded neck portion 51, that screws onto a collar 52, projecting from the motor-frame. The driving-shaft 53 of the motor projectsthrough the collar 52 and when the frame 50 is screwed onto the collar 52 will project into the neck 51. The end of the driving-shaft is connected with an insubiting-plug 54 by means of a threaded sleeve 5-"), and to the plug 54 is secured a threaded rod 56, extending into the skeleton frame 50. A flexible shaft 57 is carried by a suitable enveloping tube 58, which is secured to an extension 59 of the skeleton frame 50, but insulated therefrom by means of the insulating collar 60. The extremity of the flexible tube carries a rod. 61, having a threaded bore arranged to screw into the threaded rod 56 "in the interior of the skeleton frame 50, whereby the flexible shaft is connected with the driving-shaft of the motor. When it is desired to disconnect the flexible shaft, the fingers can be passed into the skeleton frame and unscrew the end portions 56 and 61 of the motor-shaft and flexible shaft, respectively, and thereupon the flexible shaft, with its enveloping tube, is unscrewed from the skeleton frame 50 of the motor-frame, thereby readily removing the flexible shaft from the motor. It will be observed that current is effectually prevented from passing through the motor-frame and skeleton member to the flexible tube and casing by reason of the interposed insulating-sleeve and also that the current is prevented from reaching the flexible shaft itself because of the insulatingplug 54 separating the extremity of the driving-shaft from the connecting-rod 56.

The tube 32 has a slot 321 and is externally threaded to carry three nuts 322. The end of the cable 28 is passed out of the slot below the upper nut, thence bent around the intermediate nut, and then returned through the slot into the tube and down and out at the lower end. Then the middle out is screwed up to clamp the cable against the upper nut, and thereupon the lower nut is screwed up to jam the cable against the middle nut, securely clamping the cable in such position. This permits the ready adjustment,

' of the cable.

Having thus described my invention, I claim l. The combination of an electric translating device an arm supported to swing in a vertical plane, a member having a swinging connection with the arm and carrying said device, means for counterbalancing the arm and electric device in their several positions, and leads connected with the translating device.

2. The combination of an electric translating device, a member by which such device is suspended, means for supporting said member whereby it and the translating device can be raised and lowered, a balancing-weight connected with the supporting means, and springs arranged to cooperate with the counterbalancing member whereby the translating device and supporting means are counterbalanced in a number of positions.

3. The combination of a member support translating device and said members when the swinging member is swung through apredetermined path.

4. The combination of a suspending-arm supported to swing in a vertical plane, an electric translating device, a member pivotally suspended from the arm and carrying the translating device, counterbalancing means connected with the arm and arranged to counterbalance the weight of the arm-suspending member and translating device in the several positions of the arm.

5. The combination of means for supporting the arm at one end to swing in a vertical plane, an electric translating device, a suspending member pivotally carried by the arm and secured to the translating device, a counterbalancing-weight connected with the arm and arranged to partially counterbalance the weight of the arm and translating device, a spring coacting with said weight to increase its draft on the arm when the arm is swung to decrease the horizontal distance between the vertical line of the motor and the pivotal point of the arm, and a spring arranged to counteract the draft of the weight on the arm upon the arm being swung to increase the distance between the vertical line of the mo tor and the pivotal support of the arm.

6. The combination of an arm supported to swing in a vertical plane, a suspending member pivotally carried by the arm, an electric translating device suspended by means of such member from the free end of the arm, a counterbalancing member connected by a flexible member with the free end of the arm and suspended adjacent to the pivoted end of the arm, and arranged to counterbalance the arm and translating device in the several positions of the arm.

7. The combination of an arm, means for supporting the arm at one end to swing in a vertical plane, an electric translating device, a suspending member pivotally connected with the arm and carrying the translating device, a guide member arranged before the swinging support of the arm, a flexible member I secured to the arm beyond its swinging support and passing around the guide member, and a balancing-weight secured to the flexible member and arranged to counterbalance the arm and translating device.

8. The combination of an arm, means for supporting the arm at one end to swing in a vertical plane, an electric translating device, a suspending member pivotally connected with the arm and carrying the translating dew ice, a guide member arranged above the swinging support of the arm, a flexible member secured to the arm beyond its swinging support and passing around the guide member, a balancing-weight secured to the flexi blc member and arranged to counterbalance the arm and translating device when in one position, a spring coacting with said weight to increase its draft on the flexible member when the arm is moved in one direction from said position, and a spring arranged to counteract the draft of the weight on the flexible member when the arm is swung in the opposite direction from such position.

9. The combination of an upright member supported to rotate on a vertical axis, an arm pivoted at the lower part of the upright to swing in a vertical plane, an electric translating device, a member supporting such device and having a swinging connection with the free end of the arm, a pulley mounted on the upright above the arm, a cable attached to the arm and passing around the pulley, a balancing-weight secured to the cable depending from the pulley and arranged to balance the arm and translating device.

10. The combination of an upright member supported to rotate on a vertical axis, an arm pivot-ed at the lower part of the upright to swing in a vertical plane, an electric translating device, a member supporting such device and having a swinging connection with the free end of the arm, a pulley mounted on the upright above the arm, a cable attached to the arm and passing around the pulley, a balancing-weight secured to the cable depending from the pulley and arranged to balance the arm and translating device in one position, a spring having one end connected with the upright, a detent connected with the weight and arranged to engage and distend the s ring when the weight is lowered byraising t e arm from said balanced position.

11. The combination of an upright member supported to rotate on a vertical axis, an

arm pivoted at the lower part of the upright to swing in a vertical plane, an electric translating device, a member supporting such device and having a swinging connection with the arm, a pulley mounted on the upright above the arm, a cable attached to the arm and passing around the pulley, a balancingweight secured to the. end of the cable depending from the pulley and arranged to balance the arm and translating device in one position, and a spring arranged to be compressed when the weight is moved upwardby the arm being lowered from said balanced position.

12. The combination of an upright member supported to rotate on a vertical axis, an. arm pivoted at the lower part of the upright to swing in a vertical lane, an electric translating device, a mem er supporting such device and having a swinging connection with the arm, a pulley mounted on the upright above the arm, a cable attached to the arm and assing around the pulley, a balancin weig t secured to the end of the cabledepem ing from-the pulley and arranged to balance the arm and translating device in one position, a spring having one end connected with the upright, a detent connected with the weight and arranged to engageand distend the spring when the weight is lowered by raising the arm from said balanced position, and a spring arranged to engage the detent and be compressed when the weight is moved upward by the arm being lowered from said balanced position. v

13. In a dynamo-electric device, the combination of a pair of supports, means whereby the device is pivotally suspended between said supports, the suspending means being arranged whereby the device is removable only when swung to a position transverse to its normal position'.

14. The combination of a yoke, a dynamoelectric device, means for pivotally supporting the device between the ends of the yoke, a part of each of such pivotal means being arranged to be withdrawn for a limited distance, and means for thereupon permitting removal of the device from yoke upon the device being swung to a position transverse to its normal position.

15. The combination of a yoke, a dynamoelectric device, a journal carried by each end of the yoke, bearings carried by the device and engaged by said journals, the journals being arranged to be receded in the bearings for a limited extent, the device having a channel on each side disposed at right angles with said bearings and leading therefrom and extending vertical when the device is in its normal position, the channels being arranged to permit the ends of the journals when receded to such limited positions and the device swung to a position with the channels substantially horizontal to permit withdrawal of the device from the yoke by movement of the journals through the channels.

16. The combination of a dynamo-electric device, a yoke on which the device is pivoted, brushes carried by one of said members, and insulated contact-plates carried by the other member and arranged to connect with the plates respectively when the deviceis swung on its pivotal connection with the yoke.

17. The combination of a dynamo-electric device, a yoke on which the device is pivoted, a pair of brushes carried by each end of the yoke members, and a pair of insulated contact-plates carried by the device at each side and arranged to connect with the'plates respectively when the device is swung on its pivotal connection with the yoke.

18. The combination with a motor having a frame and a shaft, of a flexible shaft, a member surrounding the flexible shaft, a skeleton support secured to the surrounding member and closing the extremity of the llexible shaft, the skeleton support being removablv fll-ldLC-lN-I'l to the frame of the motor, the motor-slut having its extremity extending into the skeleton member and removably secured to the extremity of the flexible shaft.

19. The combination with a motor having a frame and a shaft, of a flexible shaft, a member surrounding the llexible shaft, a skeleton support secured to the surrounding member and enveloping the extremity of the flexible shaft, the skeleton support being removably attached to the frame of the motor, the motor-shaft having its extremity extending into the skeleton member and secured to the extremity of the flexible shaft, a member arranged to insulate the skeleton member from the member surrounding the flexible shaft, and a member arranged to insulate the motor-shaft from the flexible shaft.

20. The combination with a motor having a frame and a shaft, of a threaded bushing projectmg from the motor-frame, a skeleton member having a threaded sleeve arranged to screw into the threaded bushing of the frame, the shaft of the motor extending through said bushing into the skeleton member, a flexible supporting member secured to the skeleton member, a flexible shaft carried by the supporting member and having a screw-threaded engagement with the end of the driven shaft extending into the skeleton. member.

ll. The combination with an electric mo tor having a frame and a shaft, of athreaded bushing projecting from the frame, a skeleton member having a threaded connection with said bushing, a flexible casing secured to the skeleton member, an insulating-bushing in said connection arranged to insulate the skeleton member from the casing, a flexible shaft carried by the casing and having a threaded extremity extending into the skeleton member, the shaft of the motor being located in said threaded bushing, an insulating-plug secured to the extremity of the latter shaft, and a threaded piece secured to the insulatingplug and projecting into the skeleton IneIn her and engaged by the threaded extremity of the flexible shaft.

22. The slotted threaded tube, three nuts on. the tube and a cable in the tube assing out around the intermediate nut and c amped by the nuts.

Signed at Nos. 9 to 15 Murray street, New York, N. Y., this 24th day of April, 1905.

JOHN F. HAMMOND.

Witnesses:

WILLIAM H. REID, FRED. J. DOLE. 

